Dyeing cellulose derivatives



i ll fldl'i l I 1*" I'll] Patented Mar. 28, 1:144

UNITED STATES PATENT OFFICE DYEING CELLULOSE DERIVATIVES Cyril M. Croft and Walter H. Hindlc, Cumberland, Md., assignors to Celanese Corporation of America, a corporation of Delaware No Drawing. Application May 28, 1941, Serial No. 395,572

8 Claims.

This invention relates to the dyeing of organic derivative of cellulose fabrics, and relates more particularly to the dyeing of organic derivative of cellulose fabrics by improved methods comprising mechanical impregnation.

An object of our invention is to increase the speed of dyeing of organic derivative of cellulose fabrics.

Another object of our invention is to obtain more uniform dyeings of organic derivative of cellulose fabrics and to obtain said dyeings more rapidly and economically.

Still another object of our invention is the elimination of overdyed creases, shaded selvedges, endedness, overdyed seam bars and other defects in dyed fabrics.

Other objects of our invention will appear from the following detailed description.

In the coloration of fabrics by means of dye baths it is highly desirable that the depth of shade desired in the fabric be reached in as short an immersion time and with as little handling of the material as possible. In this way, an economical production level may be maintained for the apparatus used in processing the fabrics in the dye plant. When dyeing organic derivative of cellulose fabrics, however, and especially organic derivative of cellulose fabrics of a fairly heavy and/or compact construction, it has been found that these materials are dyed more slowly than other textile materials since they are less absorbent and the dye liquor in the dye bath does not penetrate them as rapidly or as completely as with other textile materials. Many dyestuffs, when applied to organic derivative of cellulose fabrics from aqueous baths, yield dyeings which are far from satisfactory and consequently long periods of immersion and manipulation are usually required in order to dye the fabrics in sumciently deep, non-fugitive and non-crocking shades.

We have now discovered that organic derivative' of cellulose fabrics may be dyed rapidly in deep, level shades if the dyestuffs employed are dissolved in an organic liquid medium comprising a lower aliphatic alcohol and the resulting dye solution applied to the textile material by mechanical impregnation methods followed by a topping operation to desired shade on a winch or jig with an alcohol-free dye bath of suitable composition. This new combination dyeing process is especially applicable to the dyeing of organic derivative of cellulose fabrics of compact construction, such as sharkskins, and fabrics which are closely woven and of fairly heavy structure. By employing this novel process, the

fabrics may be dyed to shade in an unusually short period of time. The number of ends the fabric must be given on the winch or jig is reduced considerably and the dyeing operation may be carried out without any danger of cracking the fabric. The resulting dyed fabrics are entirely acceptable commercially and are unusually free of overdyed creases, shaded selvedges, endedness and overdyed seam bars, the difllculties usually arising where the dyeing is carried out entirely on the winch or Jig.

Various dyestuffs may be employed. dyestuffs may be acid dyes which are used for the dyeing of wool and which normally show little or no aiilnity for organic derivatives of cellulose, or they may be those dyes which are relatively insoluble in water and which are applied to organic derivative of cellulose materials in the form of aqueous dispersions after being specially solubilized. When these dyestuffs are applied to organic derivative of cellulose materials by mechanical impregnation methods in alcoholic solutions and said mechanical impregnation is followed by treatment on a winch or jig in accordance with our process, the resulting dyeings are brilliant and of uniform depth, and level, even, shades may be obtained without difficulty over the entire length of the fabric being processed. The amount of dyestuflf dissolved in the alcoholic dye liquor will, of course, vary depending upon the final shade desired in the material being dyed and may be from 0.01% to 6.0% based on the weight of the material. In the dye bath employed for the topping operation, we have found These that only to of this amount of dyestuff need be used to obtain the desired shade.

The lower aliphatic alcohols which are suitable for use in the dye bath may be those alcohols which are solvents for the dyestuffs employed and which exert at least a swelling or softening action on the organic derivatives of cellulose. While we prefer to employ ethyl alcohol in the dye liquor, other alcohols such as methyl alcohol, propyl alcohol, isopropyl alcohol, n-butyl alcohol, secondary butyl alcohol, tertiary butyl alcohol, n-amyl alcohol, secondary amyl alcohol and tertiary amyl alcohol, or mixtures of these alcohols may be used. The amount of the alcohol used in the dye liquor will vary depending on the alcohol or alcohols used, but should comprise at least 70% by weight of the dye bath. Where ethyl alcohol is being used, the dye liquor should preferably contain from about 75% to 85% by weight of the alcohol.

The dye liquor may be applied to the organic derivative of cellulOse materials by any convenient method of mechanical impregnation but we preferably employ padding. Thus, a fabric may be passed through a solution of the dyestuff, then between nipping rolls of 9, padding mangle which act to thoroughly impregnate the fabric with the dye liquor, and, after the fabric is suitably dried as by passing it through a heated chamber, it is then passed to a winch 0r jig where it is topped to the desired shade with an ancohol-free dye bath of suitable composition. The fabric may be processed through the padding mangle at speeds ranging up to 45 yards per minute and the final shade may be reached by topping with 2 to 12 ends on the winch or jig in from 1 to 6 hours. In the usual dyeing process where fabrics of like construction are dyed directly on a winch or jig without prior padding, shades of like depth may be reached only after processing the fabric for 16 to 40 ends taking from 8 to hours. Even under the latter circumstances a large proportion of the fabrics are commercially unsatisfactory due to various faults, a disadvantage substantially eliminated by our process. It can be seen that not only are the difiiculties encountered in prior processes overcome by our novel process, but, in addition, the time necessary to dye a given fabric to shade is shortened considerably. This enables a substantial increase in production to be obtained with only the addition of a padding device to the processing equipment. Not only may production frequently be doubled, but we have even been able to treble the production of certain dyed fabrics on a, single winch or Jig.

The organic derivative of cellulose comprising the fabrics which may be dyed in accordance with our process are cellulose esters and cellulose ethers. Examples of cellulose esters are cellulose acetate, cellulose propionate, cellulose butyrate and mixed esters, such as cellulose acetatepropionate and cellulose acetate-butyrate, while examples of cellulos ethers are ethyl cellulose and benzylcellulose. Not only may fabrics woven from bright or unpigmented yarns of an organic derivative of cellulose be dyed as described, but unusually desirable results are obtained where fabrics woven of pigment yarns aredyed in accordance with our process. In addition the present process may also be applied to mixed materials containing organic derivatives of cellulose yarns and yarns or fibers of other material such as cotton, silk, wool or regenerated cellulose. In

this way differential dyeings may be obtained 75 Water where the dyes used have no aflinity for the other textile materials present, or union dyeings may be obtained if dyes having an affinity for the cotton, silk, wool or regenerated cellulose are incorporated in the dye liquor used for padding and in the dye bath used in the topping treatment on the winch or jig.

In order further to illustrate our invention, but without being limited thereto, the following examples are given:

Example I A dye bath is made up with the following composmcm: Parts by weight Celiiton Fast Blue AF conc. (the probable formula of which is l-methylamino-Z- carboxy amide 4-isopropyl-amino-anthraquinone) 275 Hydroxy-amino-anthraquinone 25 4-halo-2-nitro-4'-alkoxy-diphenylamine 35 Ethyl alcohol 75,000 Water 25,000

A cellulose acetate fabric of a heavy, sharkskin weave is scoured on a jig, tenter dried and is then dyed with the dye bath of the above composition. The fabric to be dyed is first passed through a trough containing the dye liquor, maintained at a temperature of 20 to 30 0., at a rate of 20 yards per minute. After moving through the dye bath, the fabric is then passed to the nip of a two roller padding mangle where it is thoroughly impregnated with the liquid. The nip of the rolls of the padding mangle are so adjusted that the fabric retains 65% of its own weight of the dye liquor, From the nip of the padding mangle the fabric is passed to a drying chamber where it is dried by circulating air heated to 95 C. After being dried the fabric is run on a jig through a dilute ammonia solution, rinsed in warm water and is then topped on the jig to the desired shade in 4 hours with the number of ends necessary being about 8. The dye liquor employed for topping is maintained at C. and is of the following composition:

Parts by weight The resulting fabric is dyed a light blue shade and the fabric is unusually free of faults such as shaded selvedges, endedness, overdyed seam bars and overdyed creases. Without preliminary padding the same shade is reached on the jig alone with a minimum of 16 ends and the entire dyeing operation requires 8 hours.

Example II A cellulose acetate fabric of sharkskin weave is pad-dyed as described in Example I with a dye bath of th following composition: '1

Parts by weight 1 Celiiton Fast Blue AF conc 650 Dinitro-amino-diphenylamine 400 Dihalogenated-4-nitro-benzene-azodioxyalkyl-chloraniline 35 Ethyl alcohol 75,000 25,000

After being dried, the fabric is then tapped to the The resulting fabric is dyed a medium blue shade and is unusually free of dyeing faults. The fabric is topped to shade in hours and the number of ends necessary are 10. Without the preliminary padding the same shade is reached on the jig alone with a minimum of 20 ends and the entire dyeing operation requires hours.

Example III A cellulose acetate fabric of a twill weave and of the weight usually'employed for lining materia1 is pad-dyed as described in Example I with a dye bath of the following composition:

Parts by weight Setacyl Direct Discharge Blue G (ii-chlor- 2,4 dinitro benzene-azo-Z-aminoomega hydroxyethyl 4 acetylaminoanisole) 3,000 Nitrobenzene-azo-benzene-azo-dioxyalkylchloraniline 1,200 Acylamino benzene azo -alkyl-hydroxybenzene 825 Ethyl alcohol 60,000 Water 20,000

After being dried the fabric is then topped to the desired shade on a jig. The topping bath is of the following composition:

Parts by weight Setacyl Direct Discharge Blue G (an azo dye) 300 Nitrobelizene-azo benzene azo-dioxyalkyl-chloraniline 120 Acylamino benzene-azo-alkyl-hydroxybenzene 32.5

- Soda ash 125 Triethanola'mine 500 Soap 250 Water 500,000

The fabric is dyed a dark brown shade and the desired shade is reached on the jig in 5 hours with 10 ends being necessary. Without the preliminary padding the entire dyeing operation requires 10 hours with a minimum of 20 ends.

Example I1 A mixed cellulose acetate-wool fabric is paddyed as described in Example I with a dye bath of the following composition:

After being dried the fabric is topped to shade on a winch with a toppingv dye bath of the following composition:

- Parts by weight Celliton Fast Blue AF 330 Dihalogenated-i-nitro benzene-azo dioxyallwl chloraniline Soda a Soap 1,500 Celascour 9,000 Water 3,000,000

By this treatment only the cellulose acetate in the fabric is dyed a medium blue and the wool is left undyed. The desired shade is obtained by topping on the winch in 4 hours while without a preliminary padding operation the same shade is reached on the winch with a minimum of 12 hours.

Example V A mixed fabric of cellulose acetate and viscose is pad-dyed as described in Example I with a dye bath of the following composition:

Parts by weight Celliton Fast Blue AF 375 Dinitro-amino-diphenylamine 3'15 Hydroxy-amino-anthraquinone 125 Fastusol Blue LGA (direct cotton dye) 600 Fastusol Yellow IRA (Color Index 349-0) 100 Fastusol Scarlet LB (direct cotton dye)--- Ethyl alcohol 45,000 Water 15,000

After being dried the fabric is topped to shade The entire fabric is dyed a solid green shade by this treatment. The desired shade is reached on the winch in 5 hours. Without preliminary padding the same shade is reached on the winch alone in a minimum of 12 hours.

It is to be understood that the foregoing detailed description is merely givenby way of illustration and that many variations may be made therein without departing from the spirit of our invention.

Having described our invention, what we deire to secure by Letters Patent is:

1. Method for the coloration of organic derivative of celluose textile materials, which comprises padding such textile material with an aqueous alcoholic solution of a dyestufl, said aqueous alcoholic solution comprising at least 70% by weight of a lower aliphatic alcohol which is a solvent for the dye as the sole organic liquid present, rapidly drying the padded material at an elevated temperature and then toppin said textile material to the desired shade by subjecting the material to the action of an aqueous,

7 such textile material with an aqueous alcoholic solution of a dyestuff, said aqueous alcoholic solution comprising at least 70% by weight of a lower aliphatic alcohol which is a solvent for the dye as the sole organic liquid present, rapidly drying the padded material at an elevated temperature and then topping said textile 'material to the desired shade by subjecting the material to the action of an aqueous, alcohol-free dye bath of the same dyestuif.

8. Method for the coloration of fabrics of comparatively compact construction containing yarns of an organic derivative 'of cellulose, which comprises padding the fabric with an aqueous alcoholic solution of a dyestuif, said aqueous alcoholic solution comprising at least 70% by weight of a lower aliphatic alcohol which is a solvent for the dye as the sole organic liquid present, rapidly drying the padded fabric at an elevated temperature and then topping said fabric to th desired shade by Jig dyeing the fabric with an aqueous, alcohol-free dye bath of the same dyestufl.

4. Method for the coloration of fabrics of comparatively compact comtruction containing yarn; of an organic derivative of cellulose, which comprises padding the fabric with an aqueous alcoholic solution of a dyestuil, said aqueous alcoholic solution comprising at least 70% by weight of a lower aliphatic alcohol which is a solvent for the dye as the sole organic liquid present, rapidly drying the padded fabric at an elevated temperature and then topping said fabric to the desired shade by winch dyeing the fabric with an aqueous alcohol-free dye bath of the same dyestuff.

5. Method for the coloration of fabrics of comparatively compact construction containing yarns of cellulose acetate, which comprises padding the fabric with an aqueous alcoholic olution comprising at least 70% by weight of ethyl alcohol as the sole, organic liquid present, rapidly drying the padded fabric at an elevated temperature and then topping said fabric to the desired shade by Jig dyeing the fabric with an aqueous alcohol-free dye bath of the same dyestuff.

8. Process for the coloration of organic derivative of cellulose fabrics in medium to deep shades with direct dyeing dyestuffs for organic derivative of cellulose materials,-which comprises incorporating the maJor proportion of the direct dyeing dyestuif by padding the fabric with a solution of the dyestuii in an aqueous liquid medium comprising at least 70% by weight of a lower aliphatic alcohol as the sole organic liquid present in said medium, and then rapidly drying the fabric at an elevated temperature and thereafter incorporating the remainder of the direct dyeing dyestuif by subiecting the fabric to the action of an aqueous, alcohol free dye bath containing thesaidremainderofthedyestuii'.

for cellulose acetate materials, which comprises incorporating the maior proportion of the direct dyeing dyestuf! by padding the fabric with a solution of the dyestui! in an aqueous liquid medium comprising at least 70% weight of a lower aliphatic alcohol as the organic liquid present in said medium, and rapidly drying the fabric at an elevated temperature and thereafter incorporating the remainder of the direct dyeing dyestui! by subjecting the fabric to the action of an aqueous, alcohol free dye bath containing the said the dyestuii'.

8. Process for the coloration of cellulose acetate fabrics in medium to deep shades with direct dyeing dyestuffs for cellulose acetate materials, which comprises incorporating the major proportion of the direct dyeing dyestuif by padding the fabric with a solution of the dyestui! in an aqueous liquid medium comprising at least 70% by weight of a lower aliphatic alcohol as the sole organic liquid present in said medium, and then rapidly drying the fabric at an elevated temperature and thereafter incorporating the remainder of the direct dyeing dyestuii' by winch-dyeing the fabric with an aqueous, alcohol-free dye bath containing the said remainder of the dyestufi'.

CYRIL M. CROFT. WALTER. H. HINDLE. 

